I would just say that if it costs the business to hire these individuals...and the cost can be reflected, I guess, in lower productivity and lower returns and income. Then, when the income is taxed, it's the lower income that is taxed. Implicitly there's a deduction there that is taken into account when assessing the income. There also could be more direct expenditures or expenses for the business related to the training of that person or accommodating that person and making some adjustment to the physical place of work.
All of that would be deductible at the corporate level, if it's a corporation, or even if it's not a corporation. Implicitly there's already a recognition in the system for that.